1. Field of the Invention
The present invention relates to a semiconductor laser device.
Specifically, it relates to a phase-locked semiconductor laser device having a plurality of active regions.
2. Description of the Prior Art
One theme of semiconductor laser devices in the future is to attain a high output.
As a solution to the problem, there has been proposed a phase-locked semiconductor laser device.
When active regions are juxtaposed at proper intervals and are respectively caused to emit light, the emitted laser beams interfere with one another.
And the emission light of the phase-locked semiconductor laser device becomes as if it were emergent from a single laser element. Owing to the plurality of active regions, an operation at high output becomes possible.
The phase-locked semiconductor laser device adopts such principle.
Laser devices of this type have been reported in, for example, the following literatures:
(1) APPLIED PHYSICS LETTERS, vol. 33, no. 12, December 1978, pp. 1015-1017, D. R. SCIFRES et al., "Phase locked semiconductor laser array"
(2) APPLIED PHYSICS LETTERS, vol. 34, no. 15, January 1979, pp. 162-165, W. T. Tsang et al., "A densely packed monolithic linear array of GaAs-Al.sub.x Ga.sub.1-x As strip buried heterostructure laser"
(3) European Patent Application Publication No. 10949